Ovaries are small, paired glands located on either side of the uterus. They produce eggs and secrete hormones like estrogen and progesterone. Understanding their typical dimensions and influencing factors is important for female reproductive health. This article discusses average healthy ovary size, natural variations, and medical conditions that can alter it.
Typical Ovary Dimensions
Healthy adult ovaries are almond-shaped. They typically measure 3 to 5 centimeters (cm) in length, 1.5 to 3 cm in width, and 0.6 to 1.5 cm in thickness. These dimensions are equivalent to 30-50 millimeters (mm) in length, 15-30 mm in width, and 6-15 mm in thickness.
The volume of a healthy adult ovary during reproductive years typically ranges from 3 to 10 cubic centimeters (cm³). The right and left ovaries are usually similar in size.
Natural Factors Affecting Ovary Size
Ovary size fluctuates naturally with age and the menstrual cycle. Ovarian volume increases through childhood and adolescence, peaking around age 20 at about 7.7 mL.
After age 30, ovarian volume gradually declines. During and after menopause, ovaries become significantly smaller, reducing to an average of 2.2 to 2.8 mL due to decreased follicles and hormone production. A newborn girl’s ovaries measure approximately 1 cm in diameter.
The menstrual cycle also causes temporary changes in ovarian size. During the follicular phase, ovaries are largest due to developing follicles, which are fluid-filled sacs containing immature eggs. One dominant follicle matures, potentially reaching 22 to 24 mm before releasing an egg.
After ovulation, the ruptured follicle transforms into a temporary corpus luteum, which can range from 2 to 5 cm in diameter. During early pregnancy, the corpus luteum continues to produce hormones, temporarily enlarging the ovary where ovulation occurred. This structure reaches maximum size around 10 weeks of pregnancy before resolving. If fertilization does not occur, the corpus luteum breaks down, and the ovary returns to its pre-ovulation size, signaling a new menstrual cycle.
When Ovary Size Varies from the Norm
While natural changes account for many variations, some medical conditions can cause significant differences. These situations require medical evaluation.
Ovarian cysts are fluid-filled sacs that can form on the ovary, often leading to enlargement. Functional cysts, the most common type, typically develop as part of the menstrual cycle and often resolve on their own. Other types, such as pathological cysts or very large ones, may require medical attention.
Polycystic Ovary Syndrome (PCOS) is another common condition where ovaries may appear enlarged due to multiple small follicles, often described as “polycystic” on imaging. These follicles typically range from 2 to 9 mm. While enlarged ovaries are common in PCOS, their presence alone is insufficient for diagnosis, which also considers hormonal imbalances and irregular menstrual cycles.
Endometriosis, where tissue similar to the uterine lining grows outside the uterus, can also affect ovary size. When this tissue forms on the ovaries, it can create endometriomas, sometimes called “chocolate cysts.” These cysts can cause ovarian swelling and inflammation, potentially leading to permanent damage.
Ovarian tumors, both benign (non-cancerous) and malignant (cancerous), can also enlarge ovaries. Benign tumors do not spread, while malignant tumors are cancerous and can spread. Tumor size varies widely, and larger tumors may cause symptoms like abdominal fullness or pain. Any concerns about unusual symptoms, persistent pain, or significant changes in ovary size should prompt a visit to a healthcare provider.